Hindered phenolic norbornane-2,3-dicarboximides

ABSTRACT

Compounds having the formula   WHEREIN R1 and R2 are lower alkyl, X and Y are hydrogen or, when taken together, they form a bond or an ether linkage, m is 0 to 3, and n is 0 to 2, are good ultraviolet light stabilizers for synthetic polymers.

'United States Patent 1 Stephen [451 Sept. 16, 1975 HINDERED PHENOLICNORBORNANE-2,3-DlCARBOXIMIDES [76] Inventor: John F. Stephen, 24 MillCreek Rd.,

New City, NY. 10956 [22] Filed: Dec. 28, 1973 21 1 Appl. No.: 429,235

[52] US. Cl. 260/326 C; 260/45.8 N [51] Int. Cl C07d 27/48 [58] Field ofSearch 260/326 C [56] References Cited UNITED STATES PATENTS 2/1966Bolger 260/326 OTHER PUBLICATIONS VolodKin et 21]., Chem. Abs. Vol. 57:llO65i (1962).

Primary ExaminerJoseph A.. Narcavage ABS l RACT Compounds having theformula wherein R and R are lower alkyl, X and Y are hydro gen or, whentaken together, they form a bond or an ether linkage, m is O to 3, and.n is 0 to 2, are good ul traviolet light stabilizers for syntheticpolymers.

1 1 Claims, No Drawings l-IINDERED PHENOLICNORBORNANE-Z,S-DICARBOXIMIDES DETAILED DISCLOSURE t (Ga i g OH I R2wherein R and R are the same or different (lower) alkyl groups of l to 4carbon atoms,

X and Y are hydrogen or, when taken together, they form a bond or anether linkage,

m has a value of to 3, and

" n has a value of 0 to 2.

The R and R groups can be any straight or branched chain alkyl having 1to 4 carbon atoms, such as methyl, ethyl, isopropyl, n-butyl andtert-butyl. Preferably these groups are methyl, isopropyl and tert-butylgroups. Most preferably both groups are tert-butyl.

The X and Y groups can be hydrogen or, when taken together, they mayform a bond or an ether linkage. In other words, when they form a bondthere will be a double bond between positions and 6. When they form anether linkage, an epoxy group would result.

lmides of the formula I wherein m is 0, 2, 3, and X and Y are hydrogen,and X and Y taken together form a bond can be prepared by reacting theappropriate an hydride with anappropriate amine of the formula (CH -NH 2m II followed by treatment of the resulting chloromethyl derivative withsodium or potassium cyanide, and reduction of the resultantdialkylhydroxyphenylacetonitrile to the amine. The amine when m is 3 canbe prepared 2 by reducing the appropriate3-(3,5-dialkyl-4-hydroxyphenyl)-propionitrile with lithium aluminimhydride to yield the corresponding amine. The nitrile can be preparedaccording to the method described in U.S. Pat. No. 3,121,732 wherein theappropriate dialkylphenol is reacted with acrylonitrile.

Compounds of formula I wherein m is 1 and X and Y are hydrogen, X and Ytaken ogether form a bond and X and Y taken together form an etherlinkage can be prepared by reacting the appropriate imide with theappropriate 3,5-dialkyl-4-hydroxybenzyldialkylamine of the formula R IIIwherein R and R are as defined previously and R is an alkyl group suchas methyl or ethyl in a suitable solvent such as N,N-dimethylformamide.The 3,5-dialkyl-4- hydroxybenzyldialkyl amines can be prepared asdescribed by E. P. Previc et a1, Industrial and Engineering Chemistry,53, 469 (1961).

The compounds of formula I wherein m is 0, l, 2 and 3 and X and Y areboth hydrogen can also be prepared by catalytic hydrogenation of thecorresponding compounds of formula 1 wherein X and Y taken together forma bond in the presence of a suitable catalyst such as palladium oncharcoal.

The compounds of formula I wherein m is 0, 2 and 3 and X and Y takentogether form an ether linkage can be prepared by oxidizing thecorresponding compounds of formula I wherein X and Y taken together forma bond with a suitable oxidant, such as hydrogen peroxide and variousperacids such as peracetic and mchloroperbenzoic acids5-Norbornene-endo-2,3-dicarboxylic anhydride, cis-N-tetrahydrophthalicanhydride, bicyclo[ 2.2.2]oct-5-eneendo-2,3-dicarboxylic anhydride arecommercially available.

cis-hexahydrophthalic anhydride is commercially avaialble.-Norbornane-endo-2,3-dicarboxylic anhydride can be prepared by catalyticreduction of 5- norbornene-endo-2,3-dicarboxylic anhydride. Bicycle-[2.2.2]oct-S-ane-endo-2,3-dicarboxylic anhydride can be prepared by theprocedure outlined in British Pat. No. 796,133.

cis-Hexahydrophthalimide is commercially available.Norbornane-endo-2,3-dicarboxzimide can be prepared by catalyticreduction of 5-norbornene-endo-2,3- dicarboximide using a suitablecatalyst such as palladium on charcoal. 5-Norbornene-endo-2,3-dicarboximide can be prepared by the procedure described by W. S.Worrall in J. .Amer. Chem. Soc., 82, 5707 1960).Bicyclo-[2.2.2]octane-endo-2,3- dicarhoximide and bicyclo[ 2. 2.2]oct-5-enc-2 ,3- dicarboximide can be prepared as described by F. Manabuand O. Keiko, Chem., Pharma. Bull. (Tokyo) l0,7l4(l962).

cis-N-tetrahydrophthalimide is commercially available.

Exo-5,6epoxynorb0rnane-en|d0-2,3-dicarboximide can be prepared, forexample, by the procedure of W. S. Worrall, J. Amer. Chem. Soc., 82,5707 (1960). 4,5-

Epoxycyclohexane-1,2-diearboximide can be prepared by the proceduredescribed in US. Pat. No. 2,897,208.Exo-5,6-epoxybicyclo[2.2.2]octane-endo-2.3- dicarboximide can beprepared by peracid oxidation ofbicyclo[2.2.2]oct-ene-endo-2,3-dicarboximide.

The following examples further illustrate the preparation of thecompounds without introducing any limitations.

EXAMPLE 1 N-( 3 ,5-di-tert-butyl-4-hydroxyphenyl)-5-norborneneendo-2,3dicarboximide In a nitrogen atmosphere, a stirredsolution of 5- norbornene-endo-2,3-dicarboxylic anhydride (12.3 g, 0.075mole) and 2,6-di -tert-butyl-4-aminopheno1 (16.7 g, 0.075 mole) in 150ml of xylene was heated under reflux for 6 hours, water being removedwith a Dean-Stark trap. The xylene was evaporated under reduced pressureand the residue was triturated with hexane-benzene mixture. Theresulting solid was filtered off and was recrystallized from ethanol togive 12.3 g (45%) of the desired imide, m.p. 200202.

Following the above procedure N-(3,5-dimethyl-4-hydroxyphenyl)-5-norbornene endo-2,3- dicarboximide is prepared byemploying the appropriate starting materials.

EXAMPLE 2 N-( 3,5-di-tert-butyl-4-hydroxyphenyl)-norbornaneendo-2,3dicarboximide N-( 3,5-di-tert-butyl-4-hydroxyphenyl)-5- norbornene-endo-2,3-dicarboximide (5.5 g, 0.015 mole) was dissolvedin 200 ml of ethanol and hydrogenated ,over 100 mg of 10% palladium oncharcoal in a Parr apparatus at 50 psi. The catalyst was removed byfiltration and the filtrate was evaporated under reduced pressure.Recrystallization of the resulting solid form benzene-heptanegave 4.8 g(88%) of N-(3,5-di-tertbutyl-4-hydroxyphenyl)norbornane-endo2,3-dicarboximide, m.p. 184-186.

Following the above procedureN(3-methyl-5-tertbutyl-4-hydroxypher1yl)-norbornane-endo'2,3-dicarboximide is prepared when the appropriate starting materials areused..

' EXAMPLE 3 N-( 3,5-di-tert-butyl-4-hydroxybenzyl)-norbornane- 1endo-2,3-dicarboximide In a nitrogen atmosphere, a stirred solution ofnorbornane-endo-2,3-dicarboximide 13.0 g, 0.079 mole) and2,6-di-tert-butyl-4-dimethylaminomethylphenol (21.7 g, 0.083 mole) in-100 ml of N,N-dimethylformamide was heated at l-l25 for 4 hours. Uponcooling the mixture was poured into water and the precipitated solid wastaken up in ether. The ether solution was washed with dilutehydrochloric acid and then water. The dried (Na SO solution wasevaporated under reduced pressure and the solid residue wasrecrystallized from methanol to give 19.0 g (50%) of the title imide,m.p. 158160.

Following the above procedure (N-(3,5-diisopropyl- 4-hydroxybenzyl)-norbornaneendo-2,3-dicarboximide is prepared when the appropriatestarting materials are employed.

EXAMPLE 4 N-( 3 ,5- .1i-tert-butyl-4-hydroxyphenyl )-exo-5 ,6-epoxynorbornane-endo-Z,3-dicarboximide A stirred mixture ofN-(3,5-di-tert-butyl-4- hydroxyphenyl)-5-norbornene-endo-2,3-dicarboximide (5.5 g, 0.015 mole) 25 ml of formic acid and 25 ml ofmethylene chloride was treated with 31.5% hydrogen peroxide solution(3.4 g, 0.03 mole) and the mixture was heated at40--15 for 18 hours. Thesolvent mixture was stripped off and the residue was dissolved in ether.The ether solution was washed with 10% aqueous sodium bicarbonatesolution and then water. The dried solution was evaporated and theresidue recrystallized from methanol-water to give 2.5 g (43.5%) of thedesired epoxide, m.p. l 58l60.

Following the above described procedures and employing the abovedescribed starting materials, the compounds reported in Table l havebeen prepared.

*The designation in the above formula means tcrt-hutyl gmu The compoundsof this invention are stabilizersof organic material normally subject tothermal, oxidative or actinic light deterioration. Materials which arethus stabilized include synthetic organic polymeric substances includinghomopolymers, copolymers, and mixtures thereof, such as vinyl resinsformed from the polymerization of vinyl halides or from thecopolymerization of vinyl halides with unsaturated polymerizablecompounds, e.g., vinyl esters, a,B-unsaturated acids, a,B-unsaturatedesters, a,/3-unsaturated ketones, 01,13-unsaturated aldehydes andunsaturated hydrocarbons such as butadienes and styrene; poly-a-olefinssuch as high and low density polyethylene, cross-linked polyethylene,polypropylene, poly( 4-methyl-pentene-l and the like, includingcopolymers of a-olefins; such as ethylene-propylene copolymers, and thelike; dienes such as polybutadiene, polyisoprene, and the like,including copolymers with other monomers; polyurethanes such as areprepared from polyols and organic polyisocyanates. and polyamides suchas polyhexamethylene adipamide and polycaprolactam; polyesters such aspolyethylene terephthalates; polycarbonates such as those prepared frombisphenol-A and phosgene; polyacetals such as polyethylene terephthalatepolyacetal; polystyrene, polyethyleneoxide; polyacrylics such aspolyacrylonitrile; polyphenyleneoxides such as those prepared from2,6-dimethylphenol and the like; and copolymers such as those ofpolystyrene containing copolymers of butadiene and styrene and thoseformed by the copolymerization of acrylonitrile, butadiene and/orstyrene.

Other materials which can be stabilized by the compounds of the presentinvention include lubricating oil of the aliphatic ester type, i.e., di(1 ,2-ethylene)- azelate, pentaerythritol tetracaproate, and the like;animal and vegetable derived oils, e.g., linseed oil, fat, tallow, lard,peanut oil, cod liver oil, castor oil, palm oil, corn oil, cottonseedoil, and the like; hydrocarbon materials such as gasoline, mineral oil,fuel oil, drying oil, cutting fluids, waxes, resins, and the like, saltsof fatty acids such as soaps and the likerand alkylene glycols, e.g.,B-methoxyethyleneglycol, methoxytriethyleneg lycol, triethylene glycol,octaethyleneglycol, dibutyleneglycol, dipropyleneglycol and the like.

The compounds of this invention are particularly useful as UV lightstabilizers, especially for the protection of polyolefins, for instance,polyethylene, polypropylene, poly(butene-l poly(pentene-l polymethylbutene-l poly(4-methylpentene-l various ethylene-propylenecopolymers and the like. I

In general, the stabilizers of this invention are employed from about0.01 to about 5% by weight of the stabilized composition, although thiswill vary with the particular substrate and application. An advantageousrange is from about 0.05 to about 2% and especially 0.] to about 1%.

For addition to polymeric substrates, the stabilizers can be blendedbefore polymerization or after polymerization, during the usualprocessing operations, for ex ample, by hot-milling, the compositionthen being ex truded, pressed, blow molded or the like into films,fibers, filaments, hollow spheres and the like. The heat stabilizingproperties of these compounds may advantageously stabilize the polymeragainst degradation during such processing at the high temperaturegenerally encountered. The stabilizers can also be dissolved in suitablesolvents and sprayed on the surface of films, fabrics, filaments or thelike to provide effective stabilization. Where the polymer is preparedfrom a liquid monomer as in the case of styrene, the stabilizer may bedispersed or dissolved in the monomer prior to polymerization or curing.

These compounds can also be used in combination with other additivessuch as antioxidants, sulfur containing esters such asdistearyl-,B-thiodipropionate (DSTDP), dilauryl-B-thiodipropionate(DLTDP) in an amount of from 0.0l to 2% by weight of the organicmaterial, and the like, pourpoint depressants, corrosion and rustinhibitors, dispersing agents, demulsifiers, antifoaming agents, fillerssuch as glass or other fibers, carbon black, accelerators and the otherchemicals used in rubber compounding, plasticizers, color stabilizers,diand tri-alkyland -alkylphenyl-phosphites,

heat stabilizers, ultraviolet light stabilizers, antiozonants, dyes,pigments, metal chelating agents, dyesites and the like. Oftencombinations such as these, particularly the sulfur containing esters,the phosphites and/or the ultraviolet light stabilizers will producesuperior results in certain applications to those expected by theproperties of the individual components.

The following formula represents co-stabilizers which are in certaininstances very useful in combination with the stabilizers of thisinvention:

wherein R is an alkyl group having from 6 to 24 carbon atoms; and n isan integer from 1 to 6. Especially useful compounds of this type aredilauryl-B-thiodipropionate and distearyl-B-thiodipropionate. The abovecostabilizers are used in the amount of from 0.01 to 2% by weight of theorganic material, and preferably from 0.1 to 1%.

Although the compounds of this invention may to some degree also beeffective as thermal stabilizers, if the processing of the polymer iscarried out at high temperatures it is advantageous to incorporateadditional antioxidants.

In most applications, it is desirable to incorporate into the resincomposition, sufficient thermal antioxidants to protect the plasticagainst thermal and oxidative degradation. The amount of antioxidantrequired will be comparable to that of the actinic stabilizer. Namely,from about 0.005% to 5% and preferably from 0.01% to 2% by weightRepresentative of such antioxidants are phosphite esters, such astriphenylphosphite and dibutyl-phosphite and alkyl arylphosphites suchas dibutyl-phenylphosphite, and the like.

The best results have been obtained with the preferred class of thermalantioxidants, the hindered phenols. These compounds have been found toprovide the best thermal stabilization with the least discoloration inthe compositions of the invention. Amoung these phenolic antioxidantsare included the following:

di-n-octadecyl( 3- 5butyl4-hydroxy-5 -methylbenzyl )malonate2,6-di-t-butylphenol 2 ,2methylene-bis( 6-t-butyl-4-methylphenol)2,6-di-t-butylhydroquinone octadecyl-( 35-di-t-butyl-4--hydroxybenzylthio )acetate l,l, 3-tris(3-t-butyl-6-methyl-4-hydroxyphenyl butane l ,4bis( 3 ,5di-t-butyl-4-hydroxybenzyl )-2,3 -5 ,6-tetramethylbenzene 2,4'bis-( 3,5-di-t-butyl-4-hydroxyphenoxy )-6-( noctylthio)-l ,3 ,5-triazine2,4-bis-( 4-hydroxy-3 ,S-di-bbutylphenoxy )'6( noctylthioethylthio )-l,3 ,5-triazine 2 ,4-bisn-octylthio )-6-( 3,5-di-t-butyl-4-hydroxyanilino l ,3 ,S-triazine 2,4,6-tris( 4-hydroxy-3,5-di-t-butylphenoxy )-l ,3 ,5

triazine n-octadecyl-,B( 3 ,5di-t-butyl-4-hydroxyphenyl )propionaten-octadecyl-3 ,5ditbutyl-4-hydroxybenzoate 2-(n-octylthio)ethyl-Ia,S-di-t-butyl-i hydroxybenzoate stearamido N,N-bisethylene 3-(3,5-di-t-butyl-4- hydroxyphenyl )propionate} l ,2-propylene glycol bis-{3-( 3 ,5-di-t-butyl-4- hydroxyphenyl )propionate} pentaerythritoltetrakis- {3-( 3 ,S-di-t-butyl-4-hydroxyphenyl )propion ate}dioctadecyl-3,5-di-tbutyl-4-hydroxybenzylphosphonate di-n-octadecyll 3,5-di-t-butyl-4-hydroxyphenyl ethanephosphonate The above phenolichydrocarbon stabilizers are known and many are commercially available.

The above antioxidants have been listed only for the purpose ofillustration and it is important to note that any other antioxidant canbe employed with similar improved results. The above exemplifiedantioxidants and other related antioxidants which are incorporatedherein by reference, are disclosed in greater detail in the followingpatents: Netherlands patent specification No. 67/1119, issued Feb. 19,1968; Netherlands patent specification No. 68/03498 issued Sept. 18,1968; US. Pat. Nos. 3,255,191; 3,330,859, 3,644,482, 3,281,505;3,531,483, 3,285,855; 3,364,250; 3,368,997; 3,357,944 and 3,758,549.

' ARTIFICIAL LIGHT EXPOSURE TEST Deterioration of most polymers causedby ultraviolet light is so slow at ambient temperatures, even in theabsence of stabilizers, that testing of the effects of stabilizersgenerally must be conducted either at higher temperatures or in anaccelerated artificial light exposure device in order to yield resultsin a convenient period of time. The tests conducted in polymers using anartificial light exposure device is described below:

a. Sample Preparation 5 mil Film Unstabilized polypropylene powder(Hercules Profax 6501 is thoroughly blended with the indicated amountsof additives. The blended material is then milled on a two roll mill for5 minutes at 182C. The milled sheet is then compression molded at 220Cinto 5 mil thick film under a pressure of 175 psi and water cooled inthe press.

b. Testing Method This test is conducted in a FS/ BL unit, basically ofthe American Cyanamid design, which consists of 40 tubes of alternatingfluorescent sunlamps and black lights (20 of each). The 5 mil samplefilm which are mounted on 3 X 2 inch IR card holders with AX 1 inchwindows and are placed on a rotating drum 2 inches from the bulbs in theFS/ BL unit. The time in hours is noted for the development of 0.5carbonyl absorbance units as determined on an Infrared Spectophotometer.The development of carbonyl functional groups in the polymer isproportional to the amount of degradation caused by the ultravioletlight exposure.

TABLE II Light Stabilization of Polypropylene Time in Hours to 0.5Carbonyl Absorbance Units Stabilizer Formul. A Formul. B Formul. C

1. Compound of TABLE lI-Continued Light Stabilization of PolypropyleneTime in Hours to 0.5 Carbonyl Absorbance Units Formulation A contains0.271 of the indicated stabilizer and 0.571 of UV absorber 2(2'-hydroxy-3',5'-di-tert-butylphenyl )-5-chlor0hen2otriazole.

Formulation B contains 0.571 of the indicated stabilizer and 0.27: ofdi-n-octadecyl 3,5-di-tert-butyl-4-hydruxybenzyl-phosphonate which is anantioxidant. Formulation C contains 0.257: of the indicated stabilizer,0.257! of UV absorber2('.Z'-hydroxy-3'.5-di-tert-butylphcnyl)-5-chlorobcn1otriazole and 0.2%of antioxidant di n-octadccyl 3,5-di-tert-butyI4-hydroxybenzylphosphonate.

Other hindered phenolic antioxidants may be used in place ofdi-octadecyl(3,5-di-t-butyl-4-hydroxybenzyl)- phosphonate in the abovementioned compositions for example, di-n-octadecyla-(3-t-butyl-4-hydroxy-4- methylbenzyl)malonate, 2,4-bis(n-octylthio)-6-(3,4- di-t-butyl-4-hydroxyaniline)-1,3,5-triazine,octadecyl 3-( 3 ,5 -di-t-butyl-4'-hydroxyphenyl )propionate,pentaerythritol-tetrakis {3-( 3,5-di-t-butyl-4-hydroxyphenyl)}propionate,tris-(3,5-di-t-butyl-4-hydroxybenzyl )isocyanurate,2,6-di-tert-butyl-4-methylphenol, N N,N-tris-( 3 ,5-di-tert-butyl-4-hydro xybenzyl )isocyanurate, and2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)- 1 ,3 ,S-trimethylbenzyl.

The compositions of Table I are also stabilized with2(2'hydroxy-3',5-di-t-butylphenyl)-5- chlorobenzotriazole is replacedwith the following UV absorbers:

a. 2-hydroxy-4-methoxy-5-sulfobenzophenone trihydrate b.2-hydroxy-4-n-octoxybenzophenone c. {2,2'-thiobis(4-t-octylphenolate}-n-butylamine nickel I] d. p-octylphenyl salicylate e.2,2'dihydroxy-4,4'-dimethoxybenzophenone f.2(2-hydroxy-5'-methylphenyl)-benzotriazole.

EXAMPLE 14 High impact polystyrene resin containing elastomer (i.e.,butadiene-styrene) is stabilized against loss of elongation propertiesdue to exposure to ultraviolet light by incorporation of 0.3% by weightof N-(3,5- dimethyl-4-hydroxyphenyl)-5-norbornene-endo-2,3-dicarboximide.

The unstabilized resin is dissolved in chloroform and the stabilizerthen added, after whichthe mixture is cast on a glass plate and thesolvent evaporated to yield a uniform film which, upon drying, isremoved and cut up, and then pressed for 7 minutes at a temperature of163C and a pressure of 2,000 pounds per square inch into a sheet ofuniform thickness (25 mil). The sheets are then cut into stripsapproximately 4 X 0.5 inches. A portion of these strips is then measuredfor percent of elongation in the lnstron Tensile Testing Apparatus(lnstron Engineering Corporation, Quincy, Massachusetts). The remainingportions of the strips are placed in an FS/BL chamber according toExample 7(B) except that the samples are mounted and white cardboardstock and the time to 50% reduction in elongation is measured. Thestabilized polystyrene resin 'retains its elongation property longerthan the unstabilized resin.

EXAMPLE l plaques of 2 X2 inches. The plaques are then exposed in aFS/BL exposure device and color measurements made periodically using aHunter Color Difference Meter Model D25. Polyethylene stabilized withthe above compound is found to be much more stable than the unstabilizedpolyethylene or the polyethylene stabilized only with an antioxidant.

EXAMPLE 16 A quantity of SBR emulsion containing 100 g of rubber (500 mlof 20% SBR obtained from Texas U.S., Synpol 1500) previously storedunder nitrogen, is placed in a beaker and stirred vigorously. The pH ofthe emulsion is adjusted to 10.5 with a 0.5N NaOH solution.

To the emulsion is added 50 ml of NaCl solution. A 6% NaCl solutionadjusted with hydrochloric acid to a pH 1.5 is added in a thin streamwith vigorous stirring. When pH 6.5 is reached, the rubber begins tocoagulate and the addition is slowed down in order to maintain uniformagitation. The addition of the acidic 6% NaCl solution is terminatedwhen a pH 3.5 is reached. The coagulated crumb-rubber slurry at pH 3.5is stirred for V2 hour.

The coagulated rubber is isolated by filtration through cheese cloth,and rinsed with distilled water. After three subsequent washings withfresh distilled water, the coagulated rubber is dried, first at 25 mm Hgand finally to constant weight under high vacuum 1 mm) at 45C.

The dried rubber (25 g) is heated under nitrogen at 125C in a Brabendermixer and to this is added with mixing 0.5% ofN-(3,5-diisopropyl-4-hydroxybenzyl)- norbornane-endo-2,3-dicarboximide.The composition is mixed for 5 minutes after which it is cooled andcompression molded at 125C into 5 X 0.025" plaques.

The plaques are exposed to a xenon arc weatherometer and the colormeasurement (L-b) is made after 45, 125 and 290 hours. The samplesstabilized with the above compound are found to be much more lightstable than the unstabilized samples.

EXAMPLE 17 To 50 g of polyacetal resin containing 0.1% of an acidscavenger, dicyandiamide, is added 0.2% by weight ofN-(3,5-di-tert-butyl-4-hydroxyphenethyl)-5-norbornene-endo-Z,3-dicarboximide and milled for 7 minutes at 200C in aBrabender Plasti-recorder. The milled formulation is subsequentlypressed into a 40 mi] sheet at 215C at 350 psi for seconds then cooledquickly in a cold pressure at 350 psi. The stabilized sheets are thenremolded for 2 minutes at contact pressure and for 3 minutes at 300 psiat 215C to give plaques 1 /2 inch X 2% inch X mil. Thereafter, thetesting procedure described above under Artificial Light Exposure Testis followed to determine the light stability of the samples. Thestabilized samples are found to be much more stable than theunstabilized samples.

EXAMPLE 18 Unstabilized thoroughly dried polyethylene terephthalatechips are dry blended with 1.0% ofN-(3,5-ditert-butyl-4-hydroxyphenyl)-5-norborneneendo-2,3-dicarboximide. 60/10 denier multifilar'nent is melt spun at a melttemperature of 290C. The oriented fiber is wound on white cards andexposed in a Xenon Arc Fadeometer. Color measurements are madeperiodically with a Hunter Color Difference Meter Model D25. Thestabilized samples are found to be much more light stable than theunstabilized samples.

EXAMPLE 19 a. A composition comprising acrylonitrile-butadienestyreneterpolymer and 1% by weight of N-(3,5-di'tertbutyl-4-hydroxyphenyl)-cis-A -tetra hydrophthalimidc resistsembrittlement due to exposure to ultraviolet light longer than one whichdoes not contain the stabilizer.

b. A composition comprising polyurethane prepared from toluenediisocyanate and alkylene polyols and 1.0% by weight of N-(3,5-di-tertbutyl-4- hydroxybenzyl) bicyclo[2.2.2]octane-2,3-dicarboximide is more stable to sunlight, fluorescent sunlamps, blacklights and fluorescent lights than the unformulated polyurethane.

c. A composition comprising a polycarbonate prepared from bisphenol-Aand phosgene and 1% by weight ofN-(3,5-di-tert-butyl-4-hydroxyphenyl)-hexahydrophthalimide resistsdiscoloration due to expo sure to ultraviolet light longer than onewhich does not contain the stabilizer.

d. A composition comprising polymethylmethacrylate and 0.25% by weightof N-3,5-di-tertbutyl-4-hydroxybenzyl )-hexadrophthalimide resistsdiscoloration due to exposure to ultraviolet light longer than one whichdoes not contain the stabilizer.

EXAMPLE 20 a. A stabilized polyamide (nylon 6,6) is prepared byincorporating therein 0.1% of N-(3,5-di-tert-butyl-4-hydroxyphenyl)-4,5-epoxyhexahydrophthalimide. The light stability of thestabilized composition is superior to that of an unstabilized polyamide.

b. A stabilized polyphenylene oxide polymer (prepared by polymerizing2,6dirnethylpheno1 is prepared by incorporating therein 0.5% by weightof the manganese complex of N-(3,5-di-tert-butyl-4' hydroxybenzyl )-5,6-epoxy-5-n.orbornane-endo-2 ,3- dicarboximide. The stabilizedcompositions resist embrittlement due to exposure to ultraviolet lightlonger than one which does not contain the stabilizer.

c. A stabilized crystalline polystyrene is prepared by incorporatingtherein 0.1% by weight of N-( 3,5- dimethyl-4-hydroxybenzyl)-hexahydrophthalimide. The stabilized composition resists embrittlementdue to exposure to ultraviolet light longer than onewhich does notcontain the stabilizer.

What is claimed is:

l. A compound of the formula (Qui -Q on wherein drogen.

4. A compound of claim 2 wherein X and Y taken together from a covalentbond.

5. A compound of claim 2 wherein Y and Y taken together form an epoxygroup.

6. A compound of claim 1 which is N-(3,5-di-tertbutyl-4-hydroxyphenyl)-norb0rnane-endo-2,3- dicarboximide.

7. A compound of claim 1 which is N-(3,5-di-tertbutyl-4-hydroxyphenyl)-exo-5 ,6-epoxynorbornaneendo-2,3-dicarboximide.

8. A compound of claim 1 which isN(3,5-di-tertbutyl-4-hydroxyphenyl)-5-norbornene-endo-2,3-dicarboximide.

9. A compounds of claim 2, wherein X and Y together form a bond, and mand n are each zero.

10. A compound of claim 2, wherein X arid Y are each hydrogen and m andn are each zero.

11. A compound of claim 2, wherein X and Y together form an etherlinkage and m and n are each

1. A COMPOUND OF THE FORMULA
 2. A compound of claim 1 wherein R1 and R2are tert-butyl.
 3. A compound of claim 2 wherein X and Y are hydrogen.4. A compound of claim 2 wherein X and Y taken together from a covalentbond.
 5. A compound of claim 2 wherein Y and Y taken together form anepoxy group.
 6. A compound of claim 1 which isN-(3,5-di-tert-butyl-4-hydroxyphenyl)-norbornane-endo-2,3-dicarboximide.7. A compound of claim 1 which isN-(3,5-di-tert-butyl-4-hydroxyphenyl)-exo-5,6-epoxynorbornane-endo-2,3-dicarboximide.
 8. A compound of claim 1 which isN-(3,5-di-tert-butyl-4-hydroxyphenyl)-5-norbornene-endo-2,3-dicarboximide.9. A compounds of claim 2, wherein X and Y together form a bond, and mand n are each zero.
 10. A compound of claim 2, wherein X and Y are eachhydrogen and m and n are each zero.
 11. A compound of claim 2, wherein Xand Y together form an ether linkage and m and n are each zero.